diff options
| -rw-r--r-- | Documentation/networking/ip-sysctl.txt | 10 | ||||
| -rw-r--r-- | include/net/inetpeer.h | 2 | ||||
| -rw-r--r-- | include/net/ip.h | 2 | ||||
| -rw-r--r-- | net/ipv4/inetpeer.c | 280 | ||||
| -rw-r--r-- | net/ipv4/sysctl_net_ipv4.c | 14 |
5 files changed, 74 insertions, 234 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index d3d653a..3dcb26c 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -106,16 +106,6 @@ inet_peer_maxttl - INTEGER when the number of entries in the pool is very small). Measured in seconds. -inet_peer_gc_mintime - INTEGER - Minimum interval between garbage collection passes. This interval is - in effect under high memory pressure on the pool. - Measured in seconds. - -inet_peer_gc_maxtime - INTEGER - Minimum interval between garbage collection passes. This interval is - in effect under low (or absent) memory pressure on the pool. - Measured in seconds. - TCP variables: somaxconn - INTEGER diff --git a/include/net/inetpeer.h b/include/net/inetpeer.h index 8a159cc..1f0966f 100644 --- a/include/net/inetpeer.h +++ b/include/net/inetpeer.h @@ -32,7 +32,6 @@ struct inet_peer { struct inet_peer __rcu *avl_left, *avl_right; struct inetpeer_addr daddr; __u32 avl_height; - struct list_head unused; __u32 dtime; /* the time of last use of not * referenced entries */ atomic_t refcnt; @@ -56,6 +55,7 @@ struct inet_peer { struct inetpeer_addr_base redirect_learned; }; struct rcu_head rcu; + struct inet_peer *gc_next; }; }; diff --git a/include/net/ip.h b/include/net/ip.h index 66dd491..e9ea7c7 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -228,8 +228,6 @@ extern struct ctl_path net_ipv4_ctl_path[]; extern int inet_peer_threshold; extern int inet_peer_minttl; extern int inet_peer_maxttl; -extern int inet_peer_gc_mintime; -extern int inet_peer_gc_maxtime; /* From ip_output.c */ extern int sysctl_ip_dynaddr; diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c index ce616d9..dafbf2c 100644 --- a/net/ipv4/inetpeer.c +++ b/net/ipv4/inetpeer.c @@ -54,15 +54,11 @@ * 1. Nodes may appear in the tree only with the pool lock held. * 2. Nodes may disappear from the tree only with the pool lock held * AND reference count being 0. - * 3. Nodes appears and disappears from unused node list only under - * "inet_peer_unused_lock". - * 4. Global variable peer_total is modified under the pool lock. - * 5. struct inet_peer fields modification: + * 3. Global variable peer_total is modified under the pool lock. + * 4. struct inet_peer fields modification: * avl_left, avl_right, avl_parent, avl_height: pool lock - * unused: unused node list lock * refcnt: atomically against modifications on other CPU; * usually under some other lock to prevent node disappearing - * dtime: unused node list lock * daddr: unchangeable * ip_id_count: atomic value (no lock needed) */ @@ -104,19 +100,6 @@ int inet_peer_threshold __read_mostly = 65536 + 128; /* start to throw entries m * aggressively at this stage */ int inet_peer_minttl __read_mostly = 120 * HZ; /* TTL under high load: 120 sec */ int inet_peer_maxttl __read_mostly = 10 * 60 * HZ; /* usual time to live: 10 min */ -int inet_peer_gc_mintime __read_mostly = 10 * HZ; -int inet_peer_gc_maxtime __read_mostly = 120 * HZ; - -static struct { - struct list_head list; - spinlock_t lock; -} unused_peers = { - .list = LIST_HEAD_INIT(unused_peers.list), - .lock = __SPIN_LOCK_UNLOCKED(unused_peers.lock), -}; - -static void peer_check_expire(unsigned long dummy); -static DEFINE_TIMER(peer_periodic_timer, peer_check_expire, 0, 0); /* Called from ip_output.c:ip_init */ @@ -142,21 +125,6 @@ void __init inet_initpeers(void) 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL); - /* All the timers, started at system startup tend - to synchronize. Perturb it a bit. - */ - peer_periodic_timer.expires = jiffies - + net_random() % inet_peer_gc_maxtime - + inet_peer_gc_maxtime; - add_timer(&peer_periodic_timer); -} - -/* Called with or without local BH being disabled. */ -static void unlink_from_unused(struct inet_peer *p) -{ - spin_lock_bh(&unused_peers.lock); - list_del_init(&p->unused); - spin_unlock_bh(&unused_peers.lock); } static int addr_compare(const struct inetpeer_addr *a, @@ -203,20 +171,6 @@ static int addr_compare(const struct inetpeer_addr *a, u; \ }) -static bool atomic_add_unless_return(atomic_t *ptr, int a, int u, int *newv) -{ - int cur, old = atomic_read(ptr); - - while (old != u) { - *newv = old + a; - cur = atomic_cmpxchg(ptr, old, *newv); - if (cur == old) - return true; - old = cur; - } - return false; -} - /* * Called with rcu_read_lock() * Because we hold no lock against a writer, its quite possible we fall @@ -225,8 +179,7 @@ static bool atomic_add_unless_return(atomic_t *ptr, int a, int u, int *newv) * We exit from this function if number of links exceeds PEER_MAXDEPTH */ static struct inet_peer *lookup_rcu(const struct inetpeer_addr *daddr, - struct inet_peer_base *base, - int *newrefcnt) + struct inet_peer_base *base) { struct inet_peer *u = rcu_dereference(base->root); int count = 0; @@ -235,11 +188,9 @@ static struct inet_peer *lookup_rcu(const struct inetpeer_addr *daddr, int cmp = addr_compare(daddr, &u->daddr); if (cmp == 0) { /* Before taking a reference, check if this entry was - * deleted, unlink_from_pool() sets refcnt=-1 to make - * distinction between an unused entry (refcnt=0) and - * a freed one. + * deleted (refcnt=-1) */ - if (!atomic_add_unless_return(&u->refcnt, 1, -1, newrefcnt)) + if (!atomic_add_unless(&u->refcnt, 1, -1)) u = NULL; return u; } @@ -366,137 +317,96 @@ static void inetpeer_free_rcu(struct rcu_head *head) kmem_cache_free(peer_cachep, container_of(head, struct inet_peer, rcu)); } -/* May be called with local BH enabled. */ static void unlink_from_pool(struct inet_peer *p, struct inet_peer_base *base, struct inet_peer __rcu **stack[PEER_MAXDEPTH]) { - int do_free; - - do_free = 0; - - write_seqlock_bh(&base->lock); - /* Check the reference counter. It was artificially incremented by 1 - * in cleanup() function to prevent sudden disappearing. If we can - * atomically (because of lockless readers) take this last reference, - * it's safe to remove the node and free it later. - * We use refcnt=-1 to alert lockless readers this entry is deleted. - */ - if (atomic_cmpxchg(&p->refcnt, 1, -1) == 1) { - struct inet_peer __rcu ***stackptr, ***delp; - if (lookup(&p->daddr, stack, base) != p) - BUG(); - delp = stackptr - 1; /* *delp[0] == p */ - if (p->avl_left == peer_avl_empty_rcu) { - *delp[0] = p->avl_right; - --stackptr; - } else { - /* look for a node to insert instead of p */ - struct inet_peer *t; - t = lookup_rightempty(p, base); - BUG_ON(rcu_deref_locked(*stackptr[-1], base) != t); - **--stackptr = t->avl_left; - /* t is removed, t->daddr > x->daddr for any - * x in p->avl_left subtree. - * Put t in the old place of p. */ - RCU_INIT_POINTER(*delp[0], t); - t->avl_left = p->avl_left; - t->avl_right = p->avl_right; - t->avl_height = p->avl_height; - BUG_ON(delp[1] != &p->avl_left); - delp[1] = &t->avl_left; /* was &p->avl_left */ - } - peer_avl_rebalance(stack, stackptr, base); - base->total--; - do_free = 1; + struct inet_peer __rcu ***stackptr, ***delp; + + if (lookup(&p->daddr, stack, base) != p) + BUG(); + delp = stackptr - 1; /* *delp[0] == p */ + if (p->avl_left == peer_avl_empty_rcu) { + *delp[0] = p->avl_right; + --stackptr; + } else { + /* look for a node to insert instead of p */ + struct inet_peer *t; + t = lookup_rightempty(p, base); + BUG_ON(rcu_deref_locked(*stackptr[-1], base) != t); + **--stackptr = t->avl_left; + /* t is removed, t->daddr > x->daddr for any + * x in p->avl_left subtree. + * Put t in the old place of p. */ + RCU_INIT_POINTER(*delp[0], t); + t->avl_left = p->avl_left; + t->avl_right = p->avl_right; + t->avl_height = p->avl_height; + BUG_ON(delp[1] != &p->avl_left); + delp[1] = &t->avl_left; /* was &p->avl_left */ } - write_sequnlock_bh(&base->lock); - - if (do_free) - call_rcu(&p->rcu, inetpeer_free_rcu); - else - /* The node is used again. Decrease the reference counter - * back. The loop "cleanup -> unlink_from_unused - * -> unlink_from_pool -> putpeer -> link_to_unused - * -> cleanup (for the same node)" - * doesn't really exist because the entry will have a - * recent deletion time and will not be cleaned again soon. - */ - inet_putpeer(p); + peer_avl_rebalance(stack, stackptr, base); + base->total--; + call_rcu(&p->rcu, inetpeer_free_rcu); } static struct inet_peer_base *family_to_base(int family) { - return (family == AF_INET ? &v4_peers : &v6_peers); + return family == AF_INET ? &v4_peers : &v6_peers; } -static struct inet_peer_base *peer_to_base(struct inet_peer *p) +/* perform garbage collect on all items stacked during a lookup */ +static int inet_peer_gc(struct inet_peer_base *base, + struct inet_peer __rcu **stack[PEER_MAXDEPTH], + struct inet_peer __rcu ***stackptr) { - return family_to_base(p->daddr.family); -} - -/* May be called with local BH enabled. */ -static int cleanup_once(unsigned long ttl, struct inet_peer __rcu **stack[PEER_MAXDEPTH]) -{ - struct inet_peer *p = NULL; - - /* Remove the first entry from the list of unused nodes. */ - spin_lock_bh(&unused_peers.lock); - if (!list_empty(&unused_peers.list)) { - __u32 delta; + struct inet_peer *p, *gchead = NULL; + __u32 delta, ttl; + int cnt = 0; - p = list_first_entry(&unused_peers.list, struct inet_peer, unused); + if (base->total >= inet_peer_threshold) + ttl = 0; /* be aggressive */ + else + ttl = inet_peer_maxttl + - (inet_peer_maxttl - inet_peer_minttl) / HZ * + base->total / inet_peer_threshold * HZ; + stackptr--; /* last stack slot is peer_avl_empty */ + while (stackptr > stack) { + stackptr--; + p = rcu_deref_locked(**stackptr, base); delta = (__u32)jiffies - p->dtime; - - if (delta < ttl) { - /* Do not prune fresh entries. */ - spin_unlock_bh(&unused_peers.lock); - return -1; + if (atomic_read(&p->refcnt) == 0 && delta >= ttl && + atomic_cmpxchg(&p->refcnt, 0, -1) == 0) { + p->gc_next = gchead; + gchead = p; } - - list_del_init(&p->unused); - - /* Grab an extra reference to prevent node disappearing - * before unlink_from_pool() call. */ - atomic_inc(&p->refcnt); } - spin_unlock_bh(&unused_peers.lock); - - if (p == NULL) - /* It means that the total number of USED entries has - * grown over inet_peer_threshold. It shouldn't really - * happen because of entry limits in route cache. */ - return -1; - - unlink_from_pool(p, peer_to_base(p), stack); - return 0; + while ((p = gchead) != NULL) { + gchead = p->gc_next; + cnt++; + unlink_from_pool(p, base, stack); + } + return cnt; } -/* Called with or without local BH being disabled. */ struct inet_peer *inet_getpeer(struct inetpeer_addr *daddr, int create) { struct inet_peer __rcu **stack[PEER_MAXDEPTH], ***stackptr; struct inet_peer_base *base = family_to_base(daddr->family); struct inet_peer *p; unsigned int sequence; - int invalidated, newrefcnt = 0; + int invalidated, gccnt = 0; - /* Look up for the address quickly, lockless. + /* Attempt a lockless lookup first. * Because of a concurrent writer, we might not find an existing entry. */ rcu_read_lock(); sequence = read_seqbegin(&base->lock); - p = lookup_rcu(daddr, base, &newrefcnt); + p = lookup_rcu(daddr, base); invalidated = read_seqretry(&base->lock, sequence); rcu_read_unlock(); - if (p) { -found: /* The existing node has been found. - * Remove the entry from unused list if it was there. - */ - if (newrefcnt == 1) - unlink_from_unused(p); + if (p) return p; - } /* If no writer did a change during our lookup, we can return early. */ if (!create && !invalidated) @@ -506,11 +416,17 @@ found: /* The existing node has been found. * At least, nodes should be hot in our cache. */ write_seqlock_bh(&base->lock); +relookup: p = lookup(daddr, stack, base); if (p != peer_avl_empty) { - newrefcnt = atomic_inc_return(&p->refcnt); + atomic_inc(&p->refcnt); write_sequnlock_bh(&base->lock); - goto found; + return p; + } + if (!gccnt) { + gccnt = inet_peer_gc(base, stack, stackptr); + if (gccnt && create) + goto relookup; } p = create ? kmem_cache_alloc(peer_cachep, GFP_ATOMIC) : NULL; if (p) { @@ -525,7 +441,6 @@ found: /* The existing node has been found. p->pmtu_expires = 0; p->pmtu_orig = 0; memset(&p->redirect_learned, 0, sizeof(p->redirect_learned)); - INIT_LIST_HEAD(&p->unused); /* Link the node. */ @@ -534,63 +449,14 @@ found: /* The existing node has been found. } write_sequnlock_bh(&base->lock); - if (base->total >= inet_peer_threshold) - /* Remove one less-recently-used entry. */ - cleanup_once(0, stack); - return p; } - -static int compute_total(void) -{ - return v4_peers.total + v6_peers.total; -} EXPORT_SYMBOL_GPL(inet_getpeer); -/* Called with local BH disabled. */ -static void peer_check_expire(unsigned long dummy) -{ - unsigned long now = jiffies; - int ttl, total; - struct inet_peer __rcu **stack[PEER_MAXDEPTH]; - - total = compute_total(); - if (total >= inet_peer_threshold) - ttl = inet_peer_minttl; - else - ttl = inet_peer_maxttl - - (inet_peer_maxttl - inet_peer_minttl) / HZ * - total / inet_peer_threshold * HZ; - while (!cleanup_once(ttl, stack)) { - if (jiffies != now) - break; - } - - /* Trigger the timer after inet_peer_gc_mintime .. inet_peer_gc_maxtime - * interval depending on the total number of entries (more entries, - * less interval). */ - total = compute_total(); - if (total >= inet_peer_threshold) - peer_periodic_timer.expires = jiffies + inet_peer_gc_mintime; - else - peer_periodic_timer.expires = jiffies - + inet_peer_gc_maxtime - - (inet_peer_gc_maxtime - inet_peer_gc_mintime) / HZ * - total / inet_peer_threshold * HZ; - add_timer(&peer_periodic_timer); -} - void inet_putpeer(struct inet_peer *p) { - local_bh_disable(); - - if (atomic_dec_and_lock(&p->refcnt, &unused_peers.lock)) { - list_add_tail(&p->unused, &unused_peers.list); - p->dtime = (__u32)jiffies; - spin_unlock(&unused_peers.lock); - } - - local_bh_enable(); + p->dtime = (__u32)jiffies; + atomic_dec(&p->refcnt); } EXPORT_SYMBOL_GPL(inet_putpeer); diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index 57d0752..69fd720 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -398,20 +398,6 @@ static struct ctl_table ipv4_table[] = { .proc_handler = proc_dointvec_jiffies, }, { - .procname = "inet_peer_gc_mintime", - .data = &inet_peer_gc_mintime, - .maxlen = sizeof(int), - .mode = 0644, - .proc_handler = proc_dointvec_jiffies, - }, - { - .procname = "inet_peer_gc_maxtime", - .data = &inet_peer_gc_maxtime, - .maxlen = sizeof(int), - .mode = 0644, - .proc_handler = proc_dointvec_jiffies, - }, - { .procname = "tcp_orphan_retries", .data = &sysctl_tcp_orphan_retries, .maxlen = sizeof(int), |
